ODG can refer to:

• .odg, the file extension for an OpenDocument drawing file
• Ontario Drive and Gear Limited, a former company specializing in amphibious vehicles; now part of ARGO
• Old Dungeon Ghyll
• Objective difference grade
• Olive Drab Green, a color used in military clothing and equipment.
• Overseas Development Group, a fictional UK espionage agency that James Bond works for in Carte Blanche by Jeffery Deaver.

• Atlantic Sun Baseball Tournament
• Atlantic Sun conference
• Atlantic Sun Conference baseball awards
• Atlantic Sun Conference Baseball Coach of the Year
• Atlantic Sun Conference Baseball Tournament
• Atlantic Sun Conference Men's Basketball Tournament
• Atlantic Sun Tournament
• Atlantic Superior
• Atlantic Technical Center
• Atlantic Tele-Network, Inc.
• Atlantic Television Network
• Atlantic Television System
• Atlantic, Tennessee and Ohio Railroad
• Atlantic Terminal Mall
• Atlantic Terminal (Shopping Mall)
• Atlantic Terminal (shopping mall) and Atlantic Center
• Atlantic Test Range
• Atlantic (Theatre album)
• Atlantic: The Wildest Ocean on Earth
• Atlantic thorny oyster
• Atlantic Titi
• Atlantic Trading Estate
• Atlantic triangular slave trade
• Atlantic trumpetfish
• Atlantic Trust